This specification discloses a method, and its associated System and Program Storage Device and Computer Program, adapted for ‘history matching’ of numerical simulation models using a Self Organizing Map (SOM) software, the SOM being used to generate and define the ‘Regions’ among the grid blocks of the numerical simulation model during the history matching procedure.
History matching of numerical models is an inverse problem. That is, a numerical simulation model is adjusted such that, when a set of historically known input parameters are input to the model, a set of historically known output parameters or data will be generated by the model. History matching is therefore a trial and error procedure.
When ‘history matching’ a numerical simulation model, a set of historically known output parameters should be generated by the model in response to a set of historically known input parameters. However, when the set of historically known output parameters are not generated by the model in response to the set of historically known input parameters, it is necessary to multiply the value of a parameter (e.g. permeability) associated with each grid block of the numerical simulation model by a certain value. However, it is clear that the multiplier cannot be the same number for each grid block of the model. Therefore, when the simulation model represents a reservoir field, such as an oil or gas reservoir field, the engineer defines one or more ‘regions’ of the reservoir, wherein the same multiplier within a particular ‘region’ can be used to improve the history match. The selection of the ‘regions’ of the reservoir field can be accomplished in accordance with a geological model of the reservoir. Very often, one or more ‘rectangular boxes’ are used to define the ‘regions’ of the reservoir field. However, the selection of ‘rectangular boxes’ to define the ‘regions’ of the reservoir field does not ordinarily comply with nature.
In addition, the selection of ‘regions’ in accordance with a geological model is very often based on ‘static geological information’, that is, geological information that is not directly related to hydraulic parameters associated with production from a reservoir or other changes over time (e.g. permeability is derived from a correlation with porosity after the creation of the geological model).